Nearly everyone has heard of Paxlovid rebound, where COVID-19 symptoms return after taking the antiviral and then feeling better. It even happened to President Joe Biden. But new research shows it also happens to patients who don't take the medication.
“Our study suggests that people can experience rebound of symptoms and virus after feeling completely better for two days or more,” said study author Dr. Davey Smith, head of the division of infectious diseases and global public health at the University of California, San Diego
“In fact, return of symptoms is very common, with over a third of people reporting return of symptoms even without any therapy,” Smith added.
In 2020, Smith and his colleagues spent a month tracking 158 COVID-19 patients between the ages of 34 and 55. The patients were evenly divided between men and women, and no one was seriously ill when they first enrolled in the investigation.
At the same time, about four in 10 said they also struggled with some type of health condition that put them at relatively high risk for COVID complications, such as high blood pressure or obesity.
During the four-week tracking period, 5% ended up hospitalized, though none died. Throughout, all were monitored for the presence of 13 key COVID-19 symptoms, including coughing, fatigue, headaches, sore throats, stuffed nose, body and muscle pain, shortness of breath, fever, nausea, diarrhea, vomiting, and chills.
None of the patients received any treatment for COVID-19. Yet during the study, nearly 70% reported complete symptom resolution, which was defined as being symptom-free for at least 48 hours.
But during tracking, the investigators discovered that 44% of those who had experienced complete symptom relief — meaning more than one-third of all the patients in the study — went on to experience a recurrence of at least one COVID-19 symptom. Coughing, fatigue and headaches were the most commonly recurring symptoms.
The good news: About 85% of those who did experience some symptom rebound said those symptoms were mild.
Smith stressed that the issue at hand is not to be confused with long COVID, given that he and his colleagues “only looked at the 29 days after someone contracted COVID, and long COVID is beyond this.”
Even so, the analysis suggests “that many people can expect to see waxing and waning symptoms around a month after contracting COVID," he explained. "The main take away is that symptoms fluctuate, and that people can expect symptoms to fluctuate.”
The report was published online Oct. 27 in JAMA Network Open.
The findings are not a cause for alarm, suggested John Donnelly, a research investigator with the department of learning health sciences at the University of Michigan, in Ann Arbor.
“Although this study focuses only on individuals who were not treated, luckily it seems as though most of the time, both among treated and non-treated individuals, the symptoms that occur on recurrence seem to be mild,” Donnelly noted.
Why would some patients experience a rebound while others do not?
“I don't think it's clear at this point what exactly is driving rebound risk for treated and untreated individuals,” said Donnelly, who was not involved in the study.
Still, he suggested that with COVID-19 it's more likely than not “that the course of illness is not necessarily linear, with the tandem problems of recurrence” over time.
There's more detailed information on COVID-19 symptoms at the U.S. Centers for Disease Control and Prevention.
SOURCES: Davey Smith, MD, MAS, head, division of infectious diseases and global public health, and professor and vice chair of research, department of medicine, University of California, San Diego; John Donnelly, PhD, research investigator, department of learning health sciences, University of Michigan, Ann Arbor; JAMA Network Open, Oct. 27, 2022, online